Different types of disk type orienters have been used.
One such device is shown in U.S. Pat. No. 3,115,431 issued Dec. 24, 1963, to Stokes et al. This device includes the plurality of intermeshed rotating disks mounted on a plurality of substantially parallel side-by-side shafts positioned in a plane. The disks on the shafts are uniformly positioned intermediate disks on their adjacent shafts. In the arrangement described, the disks on adjacent shafts turn in the same direction, except for the last disks in the sequence which turn in the opposite direction. This type of arrangement (hereinbelow referred to as the Stoke's arrangement) has been found satisfactory particularly for use with long strands. The disclosure of the Stokes et al. patent is incorporated herein by reference.
Another similar device is shown in the Burkner U.S. Pat. No. 4,666,029 issued May 19, 1987 but wherein the disks on adjacent shafts are arranged in pairs in side by side relationship with the disks forming one of the pairs defining one side of an orienting passage and the disks forming the next axially space pair defining the other side of the passage. This arrangement (hereinafter referred to as Burkner's arrangement) is also satisfactory but the Stokes' arrangement is less complicated and appears to be about as effective in aligning the strands as the Burkner arrangement. The Burkner et al. patent is incorporated herein by reference.
U.S. Pat. Nos. 4,380,285 issued Apr. 19, 1983 to Burkner and 4,623,058 issued in Nov. 18, 1986 to Bossier each shows a combination of disks mounted on spaced parallel shafts and positioned above and intermediate stationary substantially vertical guide walls forming opposite walls of orienting passages through which the strands fall and are oriented. This type of orienter also has not been found to be particularly satisfactory for producing an end product with the required orientation and strength.
Canadian patent 920,529 issued Feb. 6, 1973 to Turner et al. shows yet another form of orienter wherein partition walls are designed to move to prevent plugging.
U.S. Pat. No. 3,807,931 issued Apr. 30, 1974 to Wood et al. describes another form of orienter which uses a number of vertically stacked decks each formed by stationary vertical fins each provided with a vibrating cap that improve movement of the wood particle there between. Each deck has a number of fins that is a multiple of the number of fins in the deck immediately above it so that the fins on the upper deck directly overlie corresponding fins on the lower deck and the flow of strands is divided by the upper deck and the divisions so formed further subdivide by the next lower deck. In this device, the spacing between the fins on the top deck is about half the average length the strands that are to be oriented and the spacing between the upper and lower deck is defined as the distance greater than the average length of the strands. The orienting system of this patent clearly would not be effective for long wafers nor would it function well for conventional length (3 to 4 inch) strands.
U.S. Patent 4,494,919 issued Jan. 22, 1985 to Knudson et al. describes another form of apparatus for orienting strands particularly suited to orienting and distributing of long strands.
It is also known to use pre-orienters as described in Crittenden's et al. U.S. Pat. No. 5,325,954, wherein two orienting decks are stacked one on top of the other with the axial spacing between the disks on the uppermost deck, significantly wider spaced than the disks on deck therebetween.
In a concurrently filed co-pending application by Barnes titled Short Strand Orienter, the concept of specific axial spacing or passage walls to size (width) and position the passages in one deck relative to those in the deck immediately thereabove is described and it is shown that significantly improved results are obtained with an arrangement wherein the passages through an upper deck are bisected into two passages by the next lower deck.
The vertical spacing between the bottom of the orienter and the top of the mat or layup being formed is very important i.e. the distance the strand are free to fall unrestrained laterally between the level where they are constrained by the walls of the orienting passages in the lowest deck of a multi-deck orienting system has also been found to be important for retaining the orientation applied to the strands in the orienter. When disks are used, the gaps between the lower peripheries of adjacent disks forming the same wall of one of the orienting passages, further contributes to the vertical spacing and loss of orientation since it raises the bottom edge of the passage significantly above the bottom edge of the lowermost point on the peripheries of the disks. This is a problem when vanes are used as the walls of the orienting passages.
Disks were initially used in orienters to reduce plugging and to separate strands of different length so that the resultant consolidated composite product had different strength characteristics due to the positioning of the strands of different length through the thickness of the product. Positioning the longer wafers near the surface improves the bending strength of a panel product.
The use of vanes significantly reduces throughput compared with the use of rotating disks as the walls of the orienting passages. Similarly, the throughput using a single orienting deck with a narrow gap to get good orientation even when rotating disks are used as the walls of the orienting passages, has been found to be relatively low and it is necessary to make the orienter longer and to open up the gap between the rotating disks to increase throughput.